Thank you. I did look for a support email address but here's what's at the bottom of the reminder emails:
Product and technical support
Order and payment support
Find an answer to your question or submit a request here (https://support.piriform.com/hc/en-us). This link sent me down a rabbit hole instead of simply providing the same email address as above which I thought was ONLY for product and technical support.
Unless you have an account in this forum, there's no way to access the required information about BILLING. Why? So, I had to create a new account despite the fact that the subscription reminders do go to an existing email account and i thought I had logged into my account in the past.
Then, in the FAQ section I tried to find 'billing' or 'account support' as an email or phone number. The reminders don't allow reply (!). On the documentation page none of the topics give any indication as to how to address this specific request. Even the request page you linked to above (which I have never been able to find a link for) doesn't specifically list billing/account as a topic.
It's annoying to be constantly reminded even if I've paid! So I removed the entire application and found another product that does a better job.